[GustavoParker]

Hello, everybody,
I work for a chemical company and I have a question concerning the compatibility of 1-hydroxyethane 1,1-diphosphonic acid (CAS: 2809-21-4) with sulfuric acid 60%.
My company manufacture a product for dissolve (with acid) and chelate (with HEDP) the Ca.
The issue is this:
take place a precipitation of crystal in the barrel after some time.
How can this be avoided?

I'm wait for your reply and sorry for my bad english.

[Arkcon]

If this is a common product, there should be some historical information on stability.  It would help to collect and try to understand the precipitate. It could simply be excess salt that just isn't meant to dissolve in 60% sulfuric.  Or maybe the excess acid is protonating and precipitating the organic salt.  Or a batch has gotten cold, and may redisolve in warmer liquid.

[GustavoParker]

If this is a common product, there should be some historical information on stability.  It would help to collect and try to understand the precipitate. It could simply be excess salt that just isn't meant to dissolve in 60% sulfuric.  Or maybe the excess acid is protonating and precipitating the organic salt.  Or a batch has gotten cold, and may redisolve in warmer liquid.

The crystal precipitating after some time.  I don't have means to run an analysis of the precipitate.